This invention is concerned with electric lamps which comprise a tungsten-halogen lamp within a reflector envelope for use, for example, in motor vehicle headlights. Examples of motor vehicle headlights are shown in U.S. Pat. Nos. 3,974,413 and 4,011,642. In the former, there is only one envelope, the reflector envelope itself, and the tungsten filament is disposed therein. In the latter, the tungsten filament is disposed within a small halogen-containing envelope, called a capsule, which is itself disposed within the reflector envelope. In neither case is it possible to adjust the position of the filament relative to the reflector, after the front lens is sealed to the reflector. The purpose of this invention is to provide for such an adjustment, since it results in more accurate focussing than do prior art methods.